- Minimum Window Substring #285

Author: ayosecu

minimum-window-substring/ayosecu.py

@@ -0,0 +1,47 @@
+from collections import Counter, defaultdict
+
+class Solution:
+    """
+        - Time Complexity: O(n), n = len(s)
+        - Space Complexity: O(m), m = len(t)
+    """
+    def minWindow(self, s: str, t: str) -> str:
+        need = Counter(t)
+        need_len = len(need)        
+        win_dic = defaultdict(int)
+        cnt = 0
+        min_range, min_len = [-1, -1], float("inf")
+
+        l = 0
+        for r in range(len(s)):
+            c = s[r]
+            win_dic[c] += 1
+
+            if c in need and win_dic[c] == need[c]:
+                cnt += 1
+
+            while cnt == need_len:
+                # Update min range
+                check_len = r - l + 1
+                if check_len < min_len:
+                    min_range = [l, r]
+                    min_len = check_len
+
+                # Move left pointer
+                win_dic[s[l]] -= 1
+                if s[l] in need and win_dic[s[l]] < need[s[l]]:
+                    cnt -= 1
+                l += 1
+
+        return s[min_range[0]:min_range[1]+1] if min_len != float("inf") else ""
+
+tc = [
+        ("ADOBECODEBANC", "ABC", "BANC"),
+        ("a", "a", "a"),
+        ("a", "aa", "")
+]
+
+sol = Solution()
+for i, (s, t, e) in enumerate(tc, 1):
+    r = sol.minWindow(s, t)
+    print(f"TC {i} is Passed!" if r == e else f"TC {i} is Failed! - Expected: {e}, Result: {r}")